I think it would be very helpful to be able to either straight up clone a store, so you have a starting point for a new store, or even clone packages. Cloning packages would be helpful both for cases within the same store, for making new similar packages more easily, or even from copying a package from one store to another.

Thanks for your suggestions @Rmcminerr . You can already clone existing packages within a project by using the 3 dots on the packages page.
However, there is no way to copy packages to another project.